The Future of Gene-Editing
Innovators
Francisco Mojica, University of Alicante, Spain
The first researcher to characterize a CRISPR locus and while working with them throughout the 1990s and in 2000, he recognized what had been reported as disparate repeat sequences had shared a common set of features (hallmarks of CRISPR sequences). In 2005, he reported that the sequences matched snippets from the genomes of bacteriophage; leading him to hypothesize that CRISPR is an adaptive immune system.
Philippe Horvath, Danisco France SAS
Scientists at Danisco wanted to see how S. thermophilus responds to a phage attack due to it being a common problem in the yogurt making industry. Horvath and their colleagues showed that Crispr systems are an adaptive immune system as they integrated new phage DNA into the Crispr array, allowing them to fight off phage in the future. They also showed that Cas9 is most likely the only protein that is required for interference.
Scientists at Danisco wanted to see how S. thermophilus responds to a phage attack due to it being a common problem in the yogurt making industry. Horvath and their colleagues showed that Crispr systems are an adaptive immune system as they integrated new phage DNA into the Crispr array, allowing them to fight off phage in the future. They also showed that Cas9 is most likely the only protein that is required for interference.
Luciano Marraffini and Erik Sontheimer, Northwestern University, Illinois
Luciano Marraffini and Erik Sontheimer, Northwestern University, Illinois
Luciano Marraffini and Erik Sontheimer, Northwestern University, Illinois
Marraffini and Sontheimer demonstrated how the target molecule was DNA not RNA and noted that the system could be a powerful tool if it could be transferred to non-bacterial systems, but it should be noted that a different type of Crispr system can target RNA.
Emmanuelle Charpentier, Umea University, Sweden and University of Vienna, Austria
They preformed small RNA sequencing on Streptococcus pyogenes that contained the CRISPR-Cas system and discovered that a second small RNA exists that is called tracrRNA. The tracrRNA forms a duplex with crRNA and guides the Cas9 to its targets.
Alexander Bolotin, French National Institute for Agricultural Research (INRA)
Through the study of the bacteria Streptococcus thermophilus, he revealed and unusual CRISPR locus that lacked some of the known Cas genes and contained novel Cas genes, including one encoding a large protein they predicted to have nuclease activity (Cas9). The spacers had homology to viral genes that share share a common sequence at one end; the sequence protospacer adjacent motif (PAM) was required for target recognition.
Eugene Koonin, US National Center for Biotechnology Information, NIH
Koonin was studying clusters of orthologous groups of proteins and proposed a hypothetical scheme for Crispr cascades as bacterial immune system based on insert structure to bacteriophage DNA in the natural spacer array, abandoning the previous hypothesis that Cas proteins comprise a DNA repair system.
John van der Oost, University of Wageningen, Netherlands
John van der Oost and colleagues showed that spacer sequences are transcribed into small RNAs to guide Cas proteins to target DNA.
Sylvain Moineau, University of Laval, Quebec City, Canada
Moineau and colleagues demonstrated that Crispr-Cas9 creates double-stranded breaks in the target DNA at precise positions (3 nucleotides upstream of the PAM). They also confirmed that Cas9 is the only protein required for cleavage in the Crispr-Cas9 system.
